There are two basic classifications of the media on which digital data are stored: Volatile and non-volatile. Data stored in volatile memory are lost when power is removed, where data stored in non-volatile memory are retained when power is removed. Data intended for high-speed short-term access is typically stored in volatile memory (cache or random access memory). Data intended for long term future access is typically stored in non-volatile memory (magnetic disks, or other storage media).
Volatile memory currently has faster access times and higher data transfer rates than non-volatile memory. This makes it an appealing alternative for systems requiring very high-speed access to data typically stored in long term, non-volatile storage devices.
Using volatile memory for long-term data storage has inherent risks, due to the loss of data when the power to the system is removed. The methods and systems described herein greatly reduce the risk of data loss, by providing a redundant power supply and back-up process, which ensure the data remain even more stable than data stored on the common magnetic disk drive.
In order to take advantage of the higher bandwidth of volatile memory, a high-speed data path is required between the host computer and the volatile memory storage device. For volatile memory storage devices located internal to the host computer, the computer expansion bus may be used to transfer data. For volatile memory storage devices located external to the host computer, a standard high-speed peripheral bus may be used to transfer data.